a few days ago i saw a post on the reddit datahoarder community asking how to backup keys and other small files for a long time.
it reminded me of a script i made some time ago to save my otp secrets in case of loss of device or a reenactment of the raivo otp incident,
so i decided to make it public on github, hope someone here finds it useful

github.com/Leviticoh/weedcup

the density is not great, about 1kB per A4 page, but it can recover from losing up to half of the printed surface and, if stored properly, paper should last very long